The present invention relates to previously unknown polymeric materials with tripodal chelating tris(diphenylphosphinomethyl)methyl groups covalently bound to surface of a polymer. These polymeric materials are easily impregnated with transition metals, after which they may serve as immobilized molecular catalysts with respect to a variety of reactions. A feature of the invention relates to a novel acylation agent useful in preparing these polymeric materials.
It is well known that the role of a catalyst is to increase the rate and selectivity of a chemical reaction. Such catalyst may be heterogeneous (insoluble in the reaction medium) or homogeneous (soluble). Each kind has some advantages and some drawbacks. The homogeneous catalysts are often well defined transition metal complexes with a high selectivity, but the separation of the catalyst from the product imposes an inherent problem. Therefore, it is desirable to immobilize such homogeneous catalysts on an insoluble support.
The homogeneous catalysts are typically transition metal complexes consisting of a transition metal ion and some ligands. Phosphine ligands are among the most common, as e.g. in the Rhone-Poulenc hydroformylation process (B. Cornils and E. Wiebus chemtech 25, 33, 1995). Phosphine ligands are furthermore suitable for covalent immobilization and phosphine-modified supports have been well known for year (G. O. Evans, C. U. Pittman Jr., R. McMillan, R. T. Beach and R. Jones J. Organomet. Chem. 67, 295, 1974; K. G. Allum, R. D. Hancock, I. V. Howell, R. C. Pitkethly and P. J. Robinson Jones J. Organomet. Chem. 87, 189, 1975).
During the past two decades, transition metal complexes of the tridentate phosphine ligand 1,1,1-tris(diphenylphosphinomethyl)ethane (commonly called triphos) have attracted increasing attention within the field of homogeneous catalysis. Thus, it has been reported that a rhodium complex with triphos is an active hydroformylation catalyst (C. Bianchini, A. Meli, M. Peruzzini, F. Vizza, P. Frediani and J. A. Ramirez Organometallics 9, 226, 1990), and a very thorough study of hydrodesulfurisation by rhodium, iridium and ruthenium complexes with triphos has been published (C. Bianchini and A. Meli in T. Weber et al. (eds.) Transition Metal Sulphides, Kluwer Academic Publishers, 1998).
It has been found that by swelling material based on a polymer resin with covalently bound triphos-type groups in a solution containing suitable transition metal salts or complexes, the metal ions are captured by the resin-bound triphos ligands. Thus, the immobilized triphos complexes are catalytically active at different reactions.
The invention provides materials, which generally are characterized by the following three parts:
polymer-linker-triphos
represented by the general chemical formula: 
where R1 is the linker and the C(R2P(R3)2)3 group is the triphos part.
R1 is selected from branched and linear alkyl group and alkyl carbonyl group optionally substituted with functional groups comprising carbonyl, alkoxy, hydroxy, amino, nitro, carboxylic or sulfonic acid and esters or amides thereof.
R2 are methylene (CH2) or substituted methylene groups. R3 are linear or branched alkyl or phenyl or substituted phenyl groups.
The polymer may be any polymer containing aromatic groups, such as polystyrene, poly vinyl pyridine, poly pyrrole, poly pyrrolidone or derivatives thereof, such as the said polymers substituted with one or more alkyl, formyl, alkyl carbonyl, alkoxy, hydroxy, amino, nitro or carboxylic or sulfonic acid and esters or amides thereof in the aromatic ring. The polymer may also be a copolymer, e.g. a grafted polymer or block-copolymer as long as aromatic groups are present for functionalization with the triphos ligand moiety.
The linker-triphos groups are covalently bound to the phenyl groups of the polymer, thus providing immobilized sites for chelations of transition metal ions.
The polymer is reacted with a novel acylating agent, 1,1,1-tris(halomethane)acetyl trifluoromethanesulphonate or an anhydride thereof whereby the 1,1,1-tris(halomethyl)acetyl group is attached to the benzene nuclei. The resulting acylated product is then recited with lithium diphenylphosphide to produce a polymer-linker-triphos of this invention. The latter material is then impregnated with a transition metal. The impregnated product has catalytic properties and may be used to catalyze the carbonylation of methanol, the hydrodesulphurization is of sulphur containing compounds and the hydroformylation of olefines.
The novel acylating agent referred to above is prepared by reacting a tris(halomethyl)acetyl halide with trifluoromethanesulphonic acid or a salt thereof.